Results A non significant threefold in crease in risk was found amo was in the paus of precision occupa duction air(95% CI 0.90 to 20.35). No increase in risk was found for premenopausal women whose major job was a managerial or rofessional occupa tion. However, an inverse relation between risk of premenopausal breast cancer and rofessional or mana having ever held a gerial job was observed(O o 53, 50% CI 0.34 to 0.82) This relation was strongest